Friction Stir Spot Welding of Al6082-T6/HDPE/Al6082-T6/HDPE/Al6082-T6 sandwich sheets: hook formation and lap shear test performance

Abstract

In the present work, the effect of shoulder surface and pin profiles during friction stir spot welding of Al6082-T6/HDPE/Al6082-T6/HDPE/Al6082-T6 sandwich sheet has been attempted. Lap shear tests are performed to evaluate the mechanical performance. It is observed during lap shear tests that a tool with square pin produced stronger joints. The square pin produced joints with moderate hook distance, hook width and hook height and larger bond area resulting in stronger joints. The joints made from tri-metallic sheet perform better than sandwich sheet joints. The tool with square pin generated a joint withstanding 1.4 kN fracture load in case of sandwich sheet, while it is 2.8 kN in case of tri-metallic sheet. The tri-metallic joints are characterized by larger bond area and larger hook distance. Nugget pull out is the failure mode seen in sandwich and tri-metallic sheets during lap shear tests. Keywords: Friction stir, Spot welding, Sandwich sheet, Lap shear test, Hook, Fracture